PTCH1 and neuroblastoma: To verify that TBSV-tLyp1 and TBSV-CooP were able to specifically target MB also in vivo, Ptch1+/− mice developing the tumor were IV injected with TBSV-WT or chimeric particles and 24 h later the absolute quantity of TBSV NPs in MB and NB was determined by qPCR.